exceptions.c

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/*
 * HW exception handling
 *
 * Copyright (C) 2008-2009 Michal Simek <[email protected]>
 * Copyright (C) 2008 PetaLogix
 *
 * This file is subject to the terms and conditions of the GNU General
 * Public License.  See the file COPYING in the main directory of this
 * archive for more details.
 */

/*
 * This file handles the architecture-dependent parts of hardware exceptions
 */

#include <linux/kernel.h>
#include <linux/signal.h>
#include <linux/sched.h>
#include <linux/kallsyms.h>
#include <linux/module.h>

#include <asm/exceptions.h>
#include <asm/entry.h>      /* For KM CPU var */
#include <linux/uaccess.h>
#include <linux/errno.h>
#include <linux/ptrace.h>
#include <asm/current.h>
#include <asm/cacheflush.h>

#define MICROBLAZE_ILL_OPCODE_EXCEPTION 0x02
#define MICROBLAZE_IBUS_EXCEPTION   0x03
#define MICROBLAZE_DBUS_EXCEPTION   0x04
#define MICROBLAZE_DIV_ZERO_EXCEPTION   0x05
#define MICROBLAZE_FPU_EXCEPTION    0x06
#define MICROBLAZE_PRIVILEGED_EXCEPTION 0x07

static DEFINE_SPINLOCK(die_lock);

void die(const char *str, struct pt_regs *fp, long err)
{
    console_verbose();
    spin_lock_irq(&die_lock);
    printk(KERN_WARNING "Oops: %s, sig: %ld\n", str, err);
    show_regs(fp);
    spin_unlock_irq(&die_lock);
    /* do_exit() should take care of panic'ing from an interrupt
     * context so we don't handle it here
     */
    do_exit(err);
}

/* for user application debugging */
asmlinkage void sw_exception(struct pt_regs *regs)
{
    _exception(SIGTRAP, regs, TRAP_BRKPT, regs->r16);
    flush_dcache_range(regs->r16, regs->r16 + 0x4);
    flush_icache_range(regs->r16, regs->r16 + 0x4);
}

void _exception(int signr, struct pt_regs *regs, int code, unsigned long addr)
{
    siginfo_t info;

    if (kernel_mode(regs)) {
        die("Exception in kernel mode", regs, signr);
    }
    info.si_signo = signr;
    info.si_errno = 0;
    info.si_code = code;
    info.si_addr = (void __user *) addr;
    force_sig_info(signr, &info, current);
}

asmlinkage void full_exception(struct pt_regs *regs, unsigned int type,
                            int fsr, int addr)
{
#ifdef CONFIG_MMU
    addr = regs->pc;
#endif

#if 0
    printk(KERN_WARNING "Exception %02x in %s mode, FSR=%08x PC=%08x " \
                            "ESR=%08x\n",
            type, user_mode(regs) ? "user" : "kernel", fsr,
            (unsigned int) regs->pc, (unsigned int) regs->esr);
#endif

    switch (type & 0x1F) {
    case MICROBLAZE_ILL_OPCODE_EXCEPTION:
        if (user_mode(regs)) {
            pr_debug("Illegal opcode exception in user mode\n");
            _exception(SIGILL, regs, ILL_ILLOPC, addr);
            return;
        }
        printk(KERN_WARNING "Illegal opcode exception " \
                            "in kernel mode.\n");
        die("opcode exception", regs, SIGBUS);
        break;
    case MICROBLAZE_IBUS_EXCEPTION:
        if (user_mode(regs)) {
            pr_debug("Instruction bus error exception in user mode\n");
            _exception(SIGBUS, regs, BUS_ADRERR, addr);
            return;
        }
        printk(KERN_WARNING "Instruction bus error exception " \
                            "in kernel mode.\n");
        die("bus exception", regs, SIGBUS);
        break;
    case MICROBLAZE_DBUS_EXCEPTION:
        if (user_mode(regs)) {
            pr_debug("Data bus error exception in user mode\n");
            _exception(SIGBUS, regs, BUS_ADRERR, addr);
            return;
        }
        printk(KERN_WARNING "Data bus error exception " \
                            "in kernel mode.\n");
        die("bus exception", regs, SIGBUS);
        break;
    case MICROBLAZE_DIV_ZERO_EXCEPTION:
        if (user_mode(regs)) {
            pr_debug("Divide by zero exception in user mode\n");
            _exception(SIGFPE, regs, FPE_INTDIV, addr);
            return;
        }
        printk(KERN_WARNING "Divide by zero exception " \
                            "in kernel mode.\n");
        die("Divide by zero exception", regs, SIGBUS);
        break;
    case MICROBLAZE_FPU_EXCEPTION:
        pr_debug("FPU exception\n");
        /* IEEE FP exception */
        /* I removed fsr variable and use code var for storing fsr */
        if (fsr & FSR_IO)
            fsr = FPE_FLTINV;
        else if (fsr & FSR_OF)
            fsr = FPE_FLTOVF;
        else if (fsr & FSR_UF)
            fsr = FPE_FLTUND;
        else if (fsr & FSR_DZ)
            fsr = FPE_FLTDIV;
        else if (fsr & FSR_DO)
            fsr = FPE_FLTRES;
        _exception(SIGFPE, regs, fsr, addr);
        break;

#ifdef CONFIG_MMU
    case MICROBLAZE_PRIVILEGED_EXCEPTION:
        pr_debug("Privileged exception\n");
        _exception(SIGILL, regs, ILL_PRVOPC, addr);
        break;
#endif
    default:
    /* FIXME what to do in unexpected exception */
        printk(KERN_WARNING "Unexpected exception %02x "
            "PC=%08x in %s mode\n", type, (unsigned int) addr,
            kernel_mode(regs) ? "kernel" : "user");
    }
    return;
}